Typically, concrete is delivered at a job site to remote areas via a pump that pumps the concrete through a series of boom connected pipes terminating in a flexible delivery hose. The flow of concrete is typically controlled at a point remote from the delivery hose and thus even when the concrete flow is stopped at its source, it is not unusual for concrete to continue to flow or drip from the end of the delivery hose. This condition can be very undesirable at certain job sites.
One attempt to ameliorate this excessive flow condition is set forth in the current assignee's pending U.S. patent application Ser. No. 10/309,912 filed Dec. 4, 2002, which is herein incorporated by reference. In this application, a shut-off valve for use with a concrete delivery hose includes an outer rigid casing disposed around the concrete delivery hose as well as a first flexible sleeve within the casing. A second flexible sleeve is disposed within the first flexible sleeve so as to define a gas chamber between the two sleeves. A gas port extends through the casing and into the gas chamber so that pressurized gas can be introduced into the chamber causing the second sleeve to be forced radially inwardly to constrict and close the delivery hose.
While such shut-off valve has performed generally satisfactorily, it is desirable to provide an improved device with enhancements which will more immediately stop concrete discharge and eliminate spill and waste.
It is a principal object of the present invention to provide a concrete shut-off valve which is more efficiently and simply manufactured at a lower cost with a reduction in the number and machining of parts, a reduction in assembly time and the elimination of welding operations.
It is another object of the present invention to provide a concrete shut-off valve equipped with a relief valve and an off/on indicator.
It is an object of the present invention to provide a concrete shut-off valve that is easily installed and operated.
It is a further object of the present invention to provide a valve that is positioned on the outside of the delivery hose so that the valve is not in direct contact with the flow of the concrete.
It is still another object of the present invention to provide a valve that will reduce concrete spill over and/or drippage.
It is also an object of the present invention to provide a gas controlled shut-off valve.
It is an additional object of the present invention to provide various control for the shut-off valve.